Kenya's officials are investigating a bank suspected of being used to launder millions of dollars stolen by former Nigerian dictator General Sani Abacha.

Detectives from the Central Bank of Kenya's banking fraud unit are examining documents and accounts of the Trans National Bank from as far back as 1997.

They say they want to see if some of the bank's customers helped launder an estimated $100 million that General Abacha allegedly looted from Nigeria's coffers and transferred to the United States, Switzerland, Britain and other countries.

The officer in charge of the central bank's banking fraud unit, Nicholas Kamwende, says the international investigation is focusing on the bank accounts of three or four companies. He says officials are still trying to establish the identity of the individuals behind these companies and their possible connection to the previous Kenyan government.

"There are insinuations," said Mr. Kamwende, "but you cannot say, certainly, that you are investigating a particular person in the former government."

Mr. Kamwende stressed that the investigation, which is being carried out worldwide, was requested by the Nigerian government. He says that from Kenya's perspective, the transfer of money itself is not illegal. Kenya "does not have as yet money-laundering laws, so we could not look at that as a crime per se in the Kenyan statutes," he said.

The chief executive officer of Trans National Bank, Dhirendra Rana, confirms there is an international investigation of several accounts at his bank, but would not give details. "There were transactions on customers' accounts, and until the investigation proves that there was laundered money, I cannot really make an affirmative statement that it is laundered money," he said.

Mr. Rana says the amount of money involved is much less than $100 million.

Independent watchdog group Transparency International says Kenya, under the previous government, provided the ideal environment for the Nigerian money laundering.

The director of the Kenyan office of Transparency International, Gladwell Otieno, says international money launderers commonly transfer their money to what she calls less accountable regimes where the funds are deposited as proceeds from fictitious sales or capital of bogus companies. Kenya was one such country where, she said, "there was very little scrutiny, there was a high level of impunity, and there was a high level of illicit activity."

General Abacha, who died in 1998, is believed to have stolen several billion dollars from Nigeria's public coffers.

Swiss authorities, which opened their own probe in 1999, last year returned about $88 million of the looted funds to Nigeria.